lkml.org 
[lkml]   [2023]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [RFC PATCH V4 13/17] x86/sev: Add Check of #HV event in path
From


On 4/14/2023 7:02 PM, Pankaj Gupta wrote:
>> +void check_hv_pending_irq_enable(void)
>> +{
>> + struct pt_regs regs;
>> +
>> + if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP))
>> + return;
>> +
>> + memset(&regs, 0, sizeof(struct pt_regs));
>> + asm volatile("movl %%cs, %%eax;" : "=a" (regs.cs));
>> + asm volatile("movl %%ss, %%eax;" : "=a" (regs.ss));
>> + regs.orig_ax = 0xffffffff;
>> + regs.flags = native_save_fl();
>> +
>> + /*
>> + * Disable irq when handle pending #HV events after
>> + * re-enabling irq.
>> + */
>> + asm volatile("cli" : : : "memory");
> Just curious, Does the hypervisor injects irqs via doorbell page when
> interrupts are disabled with "cli" ? Trying to understand the need to
> cli/sti covering on "do_exc_hv".


Hi Pankaj:
Thanks for your review. Yes, Hypervisor still injects #HV exception
when irq was disabled check_hv_pending() is called when
there is a #HV exception. It checks irq flag and return back without
handling irq event when irq was disabled.

\
 
 \ /
  Last update: 2023-04-14 18:34    [W:0.095 / U:0.600 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site